They're stag beetles. These are quite rare, but there were two sites maybe a couple of metres apart which between them had maybe a dozen stag beetles in various stages of dismemberment. I did later that afternoon see a live one going into the hedge, but it had gone by the time I got my camera.
Stag beetles aren't just rare, they're big — the live one I saw was close to three inches in length. What had happened to kill so many of them in the same locations?
I found my answer this morning when I saw a magpie having a go at something in the same area. I managed to get to the site and scare it of. This chap was there:
He's missing a leg and I think his wing is damaged because he kept trying to take off and couldn't. He put up a pretty good fight, though, given his relative size to the magpie.
I guess that the beetles were emerging from their colony one at a time and being picked off by the magpie. If they'd all come out at once they would have stood more of a chance; indeed, I wouldn't have liked to have seen a magpie attacked by a dozen of these guys on the wing — those pincers are enormous!
I decided, given my lack of knowledge of beetle healthcare, not to take him indoors and nurse him back to fitness. He was able to crawl to the hedge and safety, though. Also, with his packing that kind of weaponry, I could have found myself in Accident & Emergency if I'd approached too close.